1. Field of the Invention
The present invention relates to an operation input device and a method of operation input, and is suitable specifically for an operation input device for issuing instructions to a computer system or a navigation system through the input operation by an operator.
2. Description of the Related Art
In the related art, a wide variety of operation input devices are employed for issuing instructions to a computer system or a navigation system through the input operation by an operator, such as a remote controller including a keyboard, mouse, trackball or joystick, or a touch panel. All these operation input devices are contact-type input devices which are operated by actually being touched by an operator, and require troublesome work.
For example, when the operator activates application software on a computer system to work thereon, the operator must use the keyboard for character input or the like and use the mouse or the trackball for specifying positions, and such utilization of different devices for different operations is quite inconvenient. In addition, in order to operate a vehicle-mounted navigation system, the driver must stop the vehicle for safety, release his/her hands from the steering wheel, and operate the joystick of the remote controller or the touch panel each time, which is quite troublesome.
In order to cope with this problem, a non-contact type technology has been developed in which the input operation is executed by detection of movement of a finger in a space (for example, see Japanese Unexamined Patent Application Publication No. 8-202480). According to the technology described in Japanese Unexamined Patent Application Publication No. 8-202480, a predetermined space corresponding to a display screen is scanned by an infrared ray, and the fact that the infrared ray is irradiated on a pointing device such as a finger which enters the space is detected by an infrared ray sensor. Then, the position in the space specified by the pointing device is obtained from the position of irradiation of the infrared ray at that time, the position on the display screen corresponding to the position in the space is determined, and an operation instruction predetermined for the specified position is provided.
However, according to the technology described in the above-described patent document, the position in space for the operation input is limited to a plane scanned by the infrared ray, and hence the pointing device such as a finger must be moved to the above-described spatial plane each time. In particular, the space in which the operation input is enabled is constantly fixed at a predetermined space corresponding to the display screen even though the operator is not necessarily at the same position with respect to the display screen. Therefore, the operator must move the pointing device such as a finger to the predetermined spatial plane irrespective of the position of the operator, and hence this device is very user-unfriendly.
The operation input device is not necessarily used by a single specific person, but may be used by another operator having a different physical constitution. However, in the technology described in the patent document, the spatial plane in which the operation input is enabled is fixed at a predetermined position as described above. Yet, the range which the operator can reach depends on the physical constitution and hence there arises a problem that an operator having a smaller body may have a difficulty to execute the input operation depending on the position of the spatial plane. There is also a problem such that since the spatial plane is determined to have an absolute positional relation with respect to the display screen, the angle with respect to the spatial plane may vary with the position of the operator, and hence errors may occur in the operation input.
There is another problem in the technology described in the above-described patent document in that there is no way to differentiate the movement of the pointing device between a movement corresponding to the operation input and other movements. Hence, every time when the pointing device enters the spatial plane, it is determined to be the operation input, whereby erroneous operation input against the user's intension might be executed.
Also, the contact-type and non-contact type operation input devices described above both can execute the operation input only for an object displayed on the display screen, and an object which is assumed to be outside the display screen cannot be operated directly.
For example, in the case of a navigation system, a map displayed on the display screen is only a small part of the entire map, and there exists part of map continuing therefrom. Even though information which is assumed to be outside the display screen can be imagined easily from information displayed in the display screen as such map information, if a point, the position of which can be estimated, is located outside the screen, the point cannot be operated directly in the related art. Therefore, the operator must perform a very troublesome operation, that is, repeat a scrolling operation until the estimated point is displayed on the screen.
As a method of inputting a command in the computer system or the navigation system, a method of indicating an indicating or pointing area shown in the display screen in the shape of a button is widely employed. For example, in the case of the touch panel, the operator inputs a command by touching the indicating area in the shape of a button displayed in the display screen.
However, when the size of the indicating area is increased, the area which displays main content information such as the map or movie is decreased, whereby the content information cannot be seen optimally. In contrast, when the size of the indicating area is reduced in order to avoid the above-described problem, accuracy of an indicating action done by the finger or the like is required, which causes a problem that the operability is degraded. Such a problem becomes obvious when the size of the display screen is not large, such as in the navigation system.